Fix clang -Wwritable-strings warnings in the Windows sandbox

sandbox/win/src/named_pipe_policy_test.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/win/windows_version.h"
 #include "sandbox/win/src/handle_closer.h"
 #include "sandbox/win/src/sandbox.h"
 #include "sandbox/win/src/sandbox_policy.h"
 #include "sandbox/win/src/sandbox_factory.h"
 #include "sandbox/win/tests/common/controller.h"
@@ skipping 91 matching lines @@
   }
 }
 
 // This tests that path canonicalization is actually disabled if we use \\?\
 // syntax.
 TEST(NamedPipePolicyTest, CreatePipeCanonicalization) {
   // "For file I/O, the "\\?\" prefix to a path string tells the Windows APIs to
   // disable all string parsing and to send the string that follows it straight
   // to the file system."
   // http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx
-  wchar_t* argv[2] = { L"\\\\?\\pipe\\test\\..\\bleh",
-                       L"\\Device\\NamedPipe\\test" };
-  EXPECT_EQ(SBOX_TEST_SUCCEEDED, NamedPipe_Create(2, argv));
+  const wchar_t* argv[2] = { L"\\\\?\\pipe\\test\\..\\bleh",
+                             L"\\Device\\NamedPipe\\test" };
+  EXPECT_EQ(SBOX_TEST_SUCCEEDED,
+            NamedPipe_Create(2, const_cast<wchar_t**>(argv)));
 }
 
 // The same test as CreatePipe but this time using strict interceptions.
 TEST(NamedPipePolicyTest, CreatePipeStrictInterceptions) {
   TestRunner runner;
   runner.GetPolicy()->SetStrictInterceptions();
 
   // TODO(nsylvain): This policy is wrong because "*" is a valid char in a
   // namedpipe name. Here we apply it like a wildcard. http://b/893603
   EXPECT_TRUE(runner.AddRule(TargetPolicy::SUBSYS_NAMED_PIPES,
                              TargetPolicy::NAMEDPIPES_ALLOW_ANY,
                               L"\\\\.\\pipe\\test*"));
 
   EXPECT_EQ(SBOX_TEST_SUCCEEDED,
             runner.RunTest(L"NamedPipe_Create \\\\.\\pipe\\testbleh"));
 
   // On XP, the sandbox can create a pipe without any help but it fails on
   // Vista+, this is why we do not test the "denied" case.
   if (base::win::OSInfo::GetInstance()->version() >= base::win::VERSION_VISTA) {
     EXPECT_EQ(SBOX_TEST_DENIED,
               runner.RunTest(L"NamedPipe_Create \\\\.\\pipe\\bleh"));
   }
 }
 
 }  // namespace sandbox